Ner and philipp itzig



trie UNITED grates PATENT IVILIIELM BUDDEUS, OF MUNICH, GERMANY, ASSIGNOR TO LUDWVIG PREUSS- NER AND PIIILIPP ITZIG, OF OHARLOTTENBURG, AND GUSTAV OIPEN IIEIMER, OF BERLIN, GERMANY.

PROCESS OF OBTAINING THORIUlVl oxlos.

SPECIFICATION forming part of Letters Patent No. 617,636, dated January 10, 1899.

Application filed July 12, 1897.- Serial No. 644,311. (No specimens.)

T alt whom it may concern: The following is a detailed description of Be it known that I, IVILHELM BUDDEUS, a what I consider the best way of carrying out citizen of the Empire of Germany, residing at my invention: Munich, in the Kingdom of Bavaria and Em- Monazite sand generally consists of a mixpire of Germany, have invented certain new ture of monazite proper, ferrous titanate, and useful Improvements in the Art of Ob- (titaniferous iron,) and zircon. Since the taining Thorium Oxids 5 and I do hereby demonazite contains the thorium oXid, it follows clare the following to be a full, clear, and exthat the proportional amount of the latter inact description of the invention, such as will creases with that of the former. A poor or :0 enable others skilled in the art to which it ap low-grade sand containing, e. g., fifteen per pertains to make and use the same. cent. of monazite contains about 0.5 per cent. The present invention relates to the art of thorium oxid. Now under my invention the obtaining thorium oXid or thoria, (ThO and zircon and titaniferous sand, amounting to more particularly to the method of treating about eighty-five per cent. in this grade of 15 monazite sands for such purpose, its object monazite sand, are almost completely sepa being to concentrate such monazite sands, rated out in an unchanged condition. Morewith a view of enriching them in thorium over, the phosphoric acid combined with the oxid. The monazite sands occurring, 6. g., in oxids of cerium, lanthanum, didymium, and North Carolina, which contain an amount of thorium, amounting in this case to about four 20 monazite varying from a few per cent.to about per cent., is concurrently thrown out. From ninety per cent, contain a corresponding one thousand kilograms of the raw material amount of thorium oxid-that is to say, from containing fifteen per cent. monazite a reabout one-fourth to four per cent. It is due sulting product of theoretically one hundred to this fact that only the high-grade sands, and ten and practically one hundred and 2 5 which contain from three to four per cent. of thirty kilograms containing about four per the oxid, have been put upon the market. cent. thorium oxid is obtained.

The purpose of this invention is to render The chemical composition of the natural the low-grade monazite sands, which contain sand or raw material is as follows: Monaan average of one per cent. of thorium oXid, zite:(OeLaDi)2O P O +ThO .P O Ferrous 3o marketable; and the said invention, with this titanate FeTiO or FeO.TiO Zircon: 8o

object in view, consists in a method whereby ZrO .SiO .H O. these lowgrade sands are enriched in the The process is conducted as follows: The thorium oxid-i. 6., converted into aproduct sand is crushed between crushing-rollers or containing from about ten per cent. to about otherwise to the fineness of the Brazilian 3 5 twenty per cent. thorium oxid, according to sand-t3 6, so that the grains are from onethe average percentage of .monazite in the raw fourth to one-half. millimeters in diameter.

material. It should not be ground fine, since the decom- The costs of carrying out the process emposition of its ingredients depends in a measbodying my invention are entirely covered by ure upon the size of the grains. The sand so a 40 the utilization of the waste products formed comminuted is then introduced into melted 9o in the courseof the process, so that the prepcaustic soda or caustic potash having a temaration of the high-grade product from the perature of about 400 to 500 centigrade. hitherto worthless low-grade sand results in This results in completely depriving the monan additional advantage whereby the highazite of its phosphoric acid and the genera- 45 grade product under my invention may be obtion of steam. The caustic alkali readily at- 5 tained more economically than similar prodtacks the grains of monazite sand having the nets hitherto employed. size above specified, leaving the ferrous tita- My invention also involves such additional nate and zircon almost entirely unchanged, features, steps, and methods as will be herehowever. The resulting mass on solidifying 5o inaftersetfortlnancl pointed out in the claims. consists in a mixture of, first, unchanged fer- IOO rous titanate and zircon; second, an extremely fine powder of the oXids of cerium, lanthanum, didymium, (which, for the sake of brevity, I will term the cerium bases,) and of thorium, together with slight amounts of ferrous titanate and zirconium oxid, and, third, phosphate of sodium or potassium with excess of unchanged caustic soda or caustic potassium. Hot water is now added to this mass, whereby the alkali phosphate and hydrate are brought into solution. The tribasic alkali phosphate readily crystallizes out of this solution in a condition ready for the market, or the phosphoric-acid radical may be recovered out of the remaining solution by precipitating it with lime water, barium, strontium, or other suitable hydrate, whereby the corresponding phosphatez'. e, the phosphate of calcium, barium, strontium, &c.-is formed and precipitated, and the entire amount of caustic alkali or alkali hydrate is recovered by separating the remaining solution from the precipitate by filtering, decanting, or other suitable methods. The remaining solution, after separation from the crystals of alkali phosphate or from the precipitatethe phosphate of calcium, barium, or other alkaline earth or equivalent-is evaporated, and the residue, after melting, is again employed for the decomposing process. The product from which the phosphoric acid and alkali have thus been separated after being thoroughly washed is now stirred with water made somewhat alkaline, whereby the lighter oxids free from phosphoric acid are suspended and are thus readily washed or separated from the heavier undecomposed grains of ferrous titanate and zircon by elutriation or decanting the water containing the lighter oXids in suspension. This is effected with extreme case and thoroughly. I The oXids thus decanted or washed off are allowed to settle and the resulting sediment is then dried. It is readily decomposed, and by reason of its fineness it does not require to be ground. This sediment or magma, which contains all of the thorium maid of the raw material, is now treated with aqueous sulfurous acid or other aqueous inorganic or organic acids for the purpose of further concentrating the percentage of the thorium oxid contained therein. As a consequence of this treatment the greater portion of the cerium bases are brought into solution, leaving a residue which contains all of the thorium oXid. This is due to the previous treatment with caustic alkali, whereby the thorium oXid has been brought into a condition wherein it is not soluble in dilute acids, while the cerium bases are completely and readily dissolved. The most suitable acid for this purpose is sulfurous acid by virtue of its cheapness and its ready manufacture at the places where the monazite sand is found. This operation may be carried out by putting the above-described sediment or magma of oxids mixed with water into a wooden vat or receptacle, which may be lined with lead on its interior, and then introducing the sulfurous acid into the mass. Since the gases generated in the calcining-furnaces, in which the sulfurous acid is prepared by calcining or roasting pyrites or other minerals yielding sulfurous acid, leave the same in a hot condition, the heat required for solution in the vats is furnished by the gases from the furnaces themselves. It should be observed, however, that such solution takes place alsoin the cold or with moderate heat, though by no means so rapidly. After the contents of the vats have been saturated with sulfurous acid the mass is allowed to stand for some time, during which the precipitate containing all of the thorium oXid readily settles to the bottom. This precipitate is readily obtained as a sediment or magma by drawing off the acid liquor which contains the cerium bases ('L'. 6., the cerium, lanthanum, and didymium compounds) and washing with water. This sediment or magma, either dried or moist, is now ready for the market as a commercial product, or it may be further treated with a View to obtaining pure thorium preparations or compounds, which can be separated from their solutions in any appropriate manner. This product is very readily worked into pure thorium compounds. Its percentage of thorium oxid Varies between ten and twenty per cent., according to the original composition of the monazite sand.

To illustrate my process, I will describe the treatment of a high-grade and of a low-grade monazite sand.

I. Monazite sand of Brazilian origin and having the following composition: thorium oxid, 3.5 per cent.; cerium bases, (oXids of cerium, lanthanum, and didymium) fiftyfive per cent; phosphoric acid, twenty-one per cent. ferrous titanate and zircon, twenty per cent; loss in roasting or calcining, 0.5 per cent. total, one hundred per cent. First, by treating with molten caustic soda and washing with water there are separated twenty per cent; second, by washing or decanting from the ferrous titanate and zircon eighteen per cent.; third, by extraction with sulfurous acid forty per cent. total, seventyeight per cent. In other words, by the first step in this process twenty per cent., by weight, of ballast or compounds worthless in the treatment of the monazite sand are eliminated from the raw material. By the second step eighteen per cent. more are removed, and by the last step forty per cent. more, making in all seventy-eight per cent. of ballast removed. From a ton or one thousand kilograms of such sand there are hence obtained two hundred kilograms of a product containing about sixteen per cent. thorium oXid.

II. Monazite sand from- North Carolina having the following composition: thorium oxid,one per cent; cerium bases, fifteen per cent; phosphoric acid, five percent; ferrous titanate and zircon, seventy-nine per cent total, one hundred per cent. First, by treating with caustic soda and washing with water there are removed five per cent; second, by washing or decanting from ferrous titanate and zircon seventy-five per cent; third, by extraction with sulfurous acid twelve per. cent; total, ninety-two per cent.that is to say, the first step of this process results in the elimination of five per cent. of ballast, the second step removes further seventy-five per cent, and the last step twelve per cent. more, making an aggregateof ninety-two per cent, by weight, of ballast removed. From a ton or one thousand kilograms of such hitherto worthless sand I hence obtain eighty kilograms of the final produet,containing 12.5 per cent. thorium oxid.

By this process I am hence enabled to separate the useless ferrous titanate and zircon sand, to obtain all of the phosphoric acid in a marketable condition, to continually recover all or that portion of the decomposing agent (the alkali hydrate) which has not been combined with the phosphoric acid, and, finally, as the most important result to obtain a marketable raw material rich in thorium oxid which is very readily manufactured into pure thorium oxid.

The process is manifestly suitable for the treatment of Brazilian monazite sand,whether the same be rich or poor in thorium oxid, and in general for the separation of thorium oxid from cerium bases, ferrous titanate, zircon, phosphoric acid, and other impurities.

From the above description it is manifest that the process embodying my invention may be considerably varied without departing from my invention. Thus other alkalies may be used instead of the sodium hydrate or caustic soda for the separation of the phosphoric acid, and any suitable acids may be employed for extracting the cerium bases. I do not therefore desire to be limited to the exact details hereinbefore set forth; but

hat I claim, and desire to secure by Letters Patent of the United States, is-

1. In the art of concentrating raw materials containing thorium, the process which consists in crushing raw materials containing the phosphates of thorium and cerium bases, together with ferrous titanate and zircon,into coarse granular form and then introducing them into molten alkali hydrate, whereby the phosphoric acid is separated and the ferrous titanate and zircon are unaffected.

2. The process, which consists in reducing monazite sand to coarse granular form and introducing the same into molten alkali hydrate, whereby the phosphoric acid is separated and the thorium and cerium bases are converted into the oxids.

3. The process which consists in treating a raw material containing phosphate of thorium, ferrous titanate and zircon with an alphosphate and then evaporating the said remaining solution.

5. The process which consists in treating a raw material containing phosphate of thorium, ferrous titanate and zircon with an alkali hydrate, then dissolving the resulting mass in water, then separating the phosphoricacid radical from the solution, then separating the remaining solution from the solid phosphate and then evaporating the said remaining solution, and then separating the thorium oxid from the residue by Washin 6. The process which consists in comminuting monazite sand and immersing the same into molten alkali hydrate, then dissolving the resulting mass in hot water, then crystal lizingout the resultant alkali phosphate, then evaporating the mother-liquor after removing the crystals, then adding water to the residue and stirring and decanting or otherwise removing the liquor containing the thorium oxid from the heavy sediment of ferrous titanate and zircon.

7. The process which consists in treating raw material containing the phosphates of thorium and of cerium bases, together with zircon and ferrous titanate with alkali hydrates, then dissolving the resulting mass in hot water, then recovering the phosphoric-acid radical from the solution, then evaporating the remaining solution, then mixing the residue with water and stirring and separating the resultant oxids of thorium and of the cerium bases from the zircon and the ferrous titanate and then treating the mixture containing the oxids of thorium and of the ocrium bases with sulfurous acid, whereby the oxids of the cerium bases are dissolved out from the mixture.

8. The process which consists in treating raw materials containing the phosphates of thorium and of the cerium bases, together with zircon and ferrous titanate, with alkali hydrates then dissolving the resulting mass in hot water, then separating the phosphoricacid radical from the solution, then evaporating the mother-liquor, then mixing the residue with water and stirring and separating the resultant oxids of thorium and of the cerium bases from the zircon and the ferrous same into molten alkali hydrate, then dissolvsnlfurous acid whereby the cerium bases are in g the resulting m ass in hot Water, then crysdissolved out and a product containing only tallizing out the resultant alkali phosphate, the thorium oXid is obtained.

then evaporating the mother-liquor after re In testimony whereof I affix my signature 5 moving the crystals, then adding water to the in presence of two Witnesses.

residue and stirring and decanting or other- WILHELM BUDDEUS Wise removing the liquor containing the thoriurn oxid from the heavy sediment of ferrous Witnesses: titanate and zircon, and then treating the W. HAUPT, IO mixture containing the thorium oXid with HENRY HASPER. 

